Question: Let $A$ be a point on the parabola $y = x^2 - 9x + 25,$ and let $B$ be a point on the line $y = x - 8.$  Find the shortest possible distance $AB.$
Solution: Let $A = (a,a^2 - 9a + 25)$ be a point on the parabola $y = x^2 - 9x + 25.$  Then the distance from $A$ to line $x - y - 8 = 0$ is
\begin{align*}
\frac{|a - (a^2 - 9a + 25) - 8|}{\sqrt{2}} &= \frac{|-a^2 + 10a - 33|}{\sqrt{2}} \\
&= \frac{|a^2 - 10a + 33|}{\sqrt{2}} \\
&= \frac{|(a - 5)^2 + 8|}{\sqrt{2}}.
\end{align*}We see that $(a - 5)^2 + 8$ is minimized when $a = 5,$ and the minimum distance is $\frac{8}{\sqrt{2}} = \boxed{4 \sqrt{2}}.$